1. Field of the Invention
The invention relates to the field of optically guided missiles and in particular to an optical guide-by-wire missile with a retainer system which provides constant loading on optical fiber leader and which controls the radius of bend during payout of the optical fiber during missile launch.
2. Description of the Prior Art
Guide-by-wire missiles are well known and have been used since at least World War II. Typically, such missiles use a metallic wire which is used to communicate guidance control commands to the missile while in flight. The wire is normally contained within a spool included within the missile body. It is led from the spool and attached to the missile by some means, typically a folded piece of adhesive tape which extends along the longitudinal length of the missile body. The wire then emerges from the adhesive tape at the missile nose and is attached to an appropriate fitting in the stationary launch tube in which the missile is disposed. The missile is fired, and moves down the length of the launch tube tearing the wire from the adhesive tape covering. After the missile has left the launch tube, the wire is completely stripped from the adhesive tape covering and begins to be played out by the spool. Electrical signals and commands can then be bidirectionally communicated along the wire.
In such prior art fly-by-wire missiles, the wire is highly malleable and resistant to the blast effect within the launch tube. Generally, the only mechanical concern with respect to the wire and its payout is that the wire be sufficient to withstand the tensile loads to which it will be subjected during launch and flight.
However, more recently, fly-by-wire missiles have become substantially more complex and require communication of a great deal more information during the relatively small flight time. For this purpose, fiber optic filaments have been substituted for metallic wires and optical signals for electrical signals. It is clearly very important that communication with the missile must be maintained during launch and flight. This becomes substantially more difficult when utilizing fragile fiberoptic filaments which are more susceptible to damage during handling and launch, not malleable, are very brittle and therefore can suffer only a limited degree of bending without fracture.
What is needed, then, is some type of system where a fiberoptic filament may be connected between the missile and its launch tube so that the fiberoptic cable may withstand the heat and blast effects of the launch and yet to prevent the cable from being bent so severely as to degrade or destroy the fiberoptic filament.